where to find the original cpp file of ROS navigation package on my computer?
I am new to ROS and I am now trying to make some modifications on the original cpp files of base_local_planner, navigation package. I can find the header files such as trajectory.h, but really have no idea about where to find the original cpp files such as trajectory.cpp on my computer, even if I can find original code on github. Are there anybody who know the location of the cpp files?